Yellow anthracene dye.



UNITED STATES PATENT OFFICE.

ROBERT E. SCHMIDT, ELBERFELD, AND PAUL TUST, OF VOHWINKEL, NEAR ELBERFELD, GERMANY, ASSIGNORS TO FARBENFABRIKEN VORM. FRIEDR. BAYER & (10., OF ELBERFELD, GERMANY, A CORPORATION OF GERMANY Specification of Letters Patent.

Patented Nov. 20, 1906.

Application filed May 24, 1906. Serial No. 318,476.

.To all whom it may concern:

Beit known that we, ROBERT E. SCHMIDT, doctor of philosophy, chemist, residing at Elberfeld, and PAUL TUST, chemist, residing at Vohwinlicl, near Elberfeld, Kingdom of Prussia, Germany, citizens of the German Empire, have invented new and useful Improvements in Yellow .Anthracene Dye, of which the following is a specification.

Our present invention relates to the production of a new dyestuff of the anthracene series from which a vat can be prepared and which dyes umnordanted cotton yellow shades from such a vat, The process for its production consists in heating beta-methylanthraquinone with sulfur.

In carrying out our process practically we can proceed. as follows, the parts beingby weigl t: A mixture of ten parts of beta-' met ylanthra uinone and forty parts of sulfur is heated 0m 250300 Centigrade for from-three to four hours until the evolution ofhydrogen sulfid ceases. After cooling, the solid melt is pulverized and freed from admixed sulfur by boiling it with an aqueous solution of sodium sulfid. The resulting product can be further purified by extraction with hot pyridin, which dissolves the excess of betamethylanthraquinone. Our new dyestuiff is a dark-yellow crystalline powder insoluble in dilute acids and alkalies, almost insoluble in glacial acetic acid which by washing with exposure to the air 40 change to pure yellow fast shades.

Having now described our invention and in what manner the same is to be performed,

-what'we claim as new, and desire to secure by Letters Patent, is

45 The herein-described new yellow dyestufi which can be obtained by heating betamethylanthraquinone with sulfur, which dyestuff is a dark-yellow crystalline powder solu-' ble in concentrated sulfuric acid with a violet 50 color; giving an orange-brown vat with hydrosulfite and caustic-soda lye, which vat dyes :unmordanted cotton orange-brown shades which shades become yellow when washed with exposure to the air, substantially .5 5

as hereinbefore described. I

In testimony whereof we have hereunto set our hands in the presence of two subscribing witnesses.

ROBERT EJSOHMIDT. PAUL TUST. Witnesses:

O'r'ro Komo,

J. A. Rrr'ransrmos.

Upon treat- 35 

